Multi-purpose dental tool



Jan. 8, 1957 A. B. CARFAGNI MULTI-PURPOSE DENTAL TOOL 7 Filed June 3, 1955 INVENTOR. fizz-Hue 5. [iii/76A v s e Fa This invention relates to a dental tool, and more particularly to a multi-purpose dental tool adapted to be used for the ready removal from the teeth of dental patients of cemented bridges, inlays and crowns.

An object of the invention is to provide an improved multi-purpose tool of the type described embodying a simplified arrangement of parts.

A further object of the invention is the provision of the tool ofthe type described which is readily convertible from a condition for use in connection with the remo'val of..cemented bridges and crowns to a condition for use in connection with the removal of cemented inlays.

Still a further objectof the invention is the provision of an inexpensive and efficiently operable dental tool of the reversible hammer-anvil type.

And yet a further object of the invention is to provide a tool of the type described wherein the force applied by the tool to a cemented replacement to be removed, is imparted solely by spring means and in which the degree of force applied is selectively controllable through selective manual control of the length of stroke of the spring-urged hammer.

These and other objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawing forming part of this specification, and in which:

Figure 1 is a view in side elevation of the subject tool, with a bridge and inlay removal attachment connected thereto;

Figure 2 is a detail view in front elevation of the tool tip, or attachment, of Figure 1;

Figure 3 is a view in side elevation of the tool, with the operating parts thereof being reversed for another form of inlay removal or inlay seating, and with a chiseltype tip connected thereto;

Figure 4 is a detail view in front elevation of the chisel-type tip of Figure 3;

Figure 5 is a detail view in side elevation of another form of attachment tip adapted for the removal of crowns; and

Figure 6 is a detail view infront elevation of the at tachment tip of Figure 5.

With reference to the drawing, the tool is comprised of a cylindrical shank 10, a cylindrically shaped holding member 12 fixedly secured to the shank, as by a set screw 14, an annular hammer member 16 slidably disposed on shank 10, a retainer nut 18 removably secured to the threaded end 20 of shank 10, a compression spring 22 freely sleeved on the shank and disposed between the holding member 12 and the hammer member 16, and an attachment tip indicated generally at 24 having an ex ternally threaded extension 26 engaged within a tapped counterbore 28 formed in shank 10 and being provided with a hook-type end 30 terminating in a rather sharply defined edge 32. The attachment tip 24 is provided with a knurled surface portion 34 to facilitate the manual gripping of said tip for attachment to and disattachment from shank 10. Holding member 12 and hammer memher 16 are likewise provided, respectively, with knurled surfaces 36 and 38 to facilitate manual gripping thereof.

Hammer member 16 is provided with a counterbore 40 at one end thereof within which there is seated and secured a resilient washer member 42, said washer member 42 being adapted to cushion the shock when the hammer member 16 is caused to strike either the retainer nut 18 or the holding member 12, as hereinafter described.

With the parts of the tool assembled as shown in Figure l, the tool is adapted for the removal of cemented bridges or inlays from the teeth of dental patients. This is done by hooking the sharply defined edge 32 of the attachment tip 24 onto an edge of a bridge or inlay. One hand of the operator is disposed in gripping relation with holding member 12 while the other hand is used to yieldingly move the hammer member 16 toward the holding member 12 against the resistance of spring 22. When the hammer member 16 is released, it is driven'by spring 22 forcibly against the retainer nut 18, with the latter serving, in effect, as the anvil member for the hammer member. The force applied by this impact is transmitted through shank 10 to tip 24, thereby applying a loosening force to the bridge or inlay engaged by tip edge 32. After repetitive hammer impacts in this fashion, the anchoring bondfor the bridge or inlay is ruptured, thus permitting removal of the particular restoration denture.

When attachment tip 24 is replaced with the attachment tip 124 of Figures 5 and 6, the two may be operated in the described manner to effect removal of a crown. Attachment tip 124 is provided with a knife edge 126, and it will thus be seen that when the tip of the knife edge is placed beneath an edge of the crown repeated impacts of hammer member 16 against anvil member 18 will effect a splitting of the crown, thus enabling ready removal thereof.

By removing retainer nut 18, hammer member 16 and spring 22, and by reversing the hammer member and re sleeving it on shank 10 with the Washer containing end disposed toward gripping member 12, followed by a sleeving of spring 22 onto the shank and replacement of retainer nut 18, said disposition of parts being shown in Figure 3, the tool is conditioned for use in a different way. A straight attachment tip 224 having a chisel edge 226 is secured to shank 10. By applying edge 226 of tip 224 to the side or edge of an inlay and by causing the hammer member to repeatedly strike the gripping member 12, which now serves, in effect, as the anvil member, the chisel edge of the attachment tip is forced into the inlay to rupture the bond securing the inlay in place, thus enabling ready removal of the inlay.

It will be appreciated that the impact force applied to a cemented replacement to be removed is directly proportional to the distance the hammer member 16 is yieldingly moved away from either retainer nut 18 or gripping member 12, as the case may be, and that therefore the impact force may be selectively controlled by the operator.

What is claimed is:

l. A device of the class described comprising an elongated shank member having upper and lower ends, a grip member fixedly secured to said shank member intermediate the ends thereof, a hammer member slidably sleeved on said shank member between the upper end thereof and said grip member, a helical spring freely sleeved on said shank member and adapted to be selectively disposed thereon in a first position between said grip member and said hammer member and in a second position between said hammer member and the upper end of said shank member, a retainer member removably secured to the upper end of said shank member adapted when secured to said upper end to prevent removal from said shank member of said spring and said hammer member and adapted when removed from said shank member to enable removal therefrom of said hammer member and spring for re-disposition of said spring from one of said positions to the other of said positions, resilient bumper means carried at one end of said hammer member adapted to cushion the impact between said hammer member and retainer member when said spring is disposed in'said first position and to cushion the im act between s id hammer member and said grip member when said spring is dis pOSGtl in Said 'SBZI'OIld POS'ifiO'I'l, 3116 "means at the IO'WCT end of said shank member for removably securing an attachmenttip thereto.

2'. A device of the class described comprising an elongated shank member having upper and lower ends, a grip member fixedly secured to said shank member intermediate the ends thereof, a hammer member slidably sleeved on said shank member between the upper 'endthereo'f and said .grip member, a retainer member removably secured to the upper end of said shank member adapted to serve as an 'anvil member for said hammer member, a helical spring freely sleeved on said "shank member between said grip member "and said hammer member adapted when said hammer member is yieldingly moved away "from said retainer member and thereafter released to drive said hammer member against said retainer member, said hammer member havin a counterbore formed in that end thereof disposed toward said retainer member, said counterbore being of larger diameter than the width of said retainer member, a complemental resilient washer seated and secured within said counterbore adapted to engage said retainer memberunder the action of said spring, and an attachment tip having a hooked lower end remov ably secured to the lower end of said shank member.

3. A device of the class described comprising an elongated shank member having upper and lower ends, a grip member fixedly secured to said shank member intermediate the ends thereof and adapted to serve as an anvil member, a hammer member slidably sleeved on said shank member between the upper end thereof and said grip member, a retainer member removably secured to the upper end of said shank member, a helical spring freely sleeved on said shank member between said hammer member and said retainer member adapted when said hammer member is yiel'dingly moved away from said grip member and thereafter released to drive said hammer member against said grip member, said hammer member having a'c'ounte'rbore formed in that end thereof disposed toward said grip member, said counterbore being of larger diameter than the width of said grip member, and a complemental resilient washer-seated and secured within said counterbore adapted to engage saidretainer member under the action of :said spring, and an attachment tip having a straight chisel-type lower end removably secured to the lower end of said shank member.

References Cited in the file "of this patent UNITED STATES :PATENTS 1,461,032 Forsyth- July 10, 1923 2,187,852 Friddle Jan. 23, 1940 2,337,971 Caviglia De'c. 28, 1943 nit-I, p 

